h1. FLUENT - Flat Plate Boundary Layer Step 6 {panel} Author: Rajesh Bhaskaran, Cornell University [Problem Specification|FLUENT - Flat Plate Boundary Layer Problem Specification] [1. Pre-Analysis & Start-up|FLUENT - Flat Plate Boundary Layer Step 1] [2. Geometry|FLUENT - Flat Plate Boundary Layer Step 2] [3. Mesh|FLUENT - Flat Plate Boundary Layer Step 3] [4. Setup (Physics)|FLUENT - Flat Plate Boundary Layer Step 4 *New] [5. Solution|FLUENT - Flat Plate Boundary Layer Step 5 *New] {color:#ff0000}{*}6. Results{*}{color} [7. Verification & Validation|FLUENT - Flat Plate Boundary Layer Step 7] {panel} {info:title=Useful Information} [Click here|SIMULATION:FLUENT - Flat Plate Boundary Layer Step 6] for the FLUENT 6.3.26 version. {info} h2. Step 6: Results h4. {color:#cc0000}Plot Velocity Vectors{color} Let's plot the velocity vectors obtained from the FLUENT solution. *Results > Graphics and Animations > Graphics > Vectors* Zoom in a little using the middle mouse button to peer more closely at the velocity vectors. \\ !step6_1.png|width=298,height=255! [Higher Resolution Image|^step6_1.png] {new window: Higher Resolution Image} ^step6_1.png{new window} \\ Remember to save the image using *Main Menu > File > Save picture* You can then select coloring, resolution and format for your picture. Then click on {color:#990099}{*}{_}Save{_}{*}{color} and give a name to the file to save it. h4. {color:#cc0000}Plot Pressure Coefficients{color} Now we will display the pressure coefficient contour but first we need to set the reference values for velocity. Go back to: *Problem Setup > Reference Values* And select {color:#990099}{*}{_}inlet{_}{*}{color} under {color:#990099}{*}{_}Compute From._{*}{color} Then go back to: *Results > Graphics and Animations > Graphics > Contours* Select {color:#990099}{*}{_}Pressure..._{*}{color}under {color:#990099}{*}{_}Contours Of{_}{*}{color}. Then select {color:#990099}{*}{_}Pressure Coefficient{_}{*}{color} from the second drop-down menu. Also, check the {color:#990099}{*}{_}Filled{_}{*}{color} checkbox and set {color:#990099}{*}{_}Levels{_}{*}{color} to 90. Then click on {color:#990099}{*}{_}Display{_}{*}{color} to update the display window. \\ !step6_002.png|width=298,height=255! [Higher Resolution Image|^step6_002.png] \\ Zoom in at the leading edge. !step6_003.png|width=298,height=255! [Higher Resolution Image|^step6_003.png] \\ Why is the pressure not constant at the leading edge of the plate? h4. {color:#cc0000}Plot Skin Friction Coefficient{color} Now we will plot the skin friction coefficient along the flat plate. *Results > Plots > XY Plot* Change {color:#990099}{*}{_}Pressure{_}{*}{color} to {color:#990099}{*}{_}Wall Fluxes{_}{*}{color}. Then, change {color:#990099}{*}{_}Wall Shear Stress{_}{*}{color} to {color:#990099}{*}{_}Skin Friction Coefficient{_}{*}{color}. Under {color:#990099}{*}{_}Surfaces{_}{*}{color}, select {color:#990099}{*}{_}plate{_}{*}{color}. !step6_004.png|width=334,height=238! Click {color:#990099}{*}{_}Plot{_}{*}{color}. !step6_005.png|width=297,height=255! [Higher Resolution Image|^step6_005.png]\\ Now, compare your solution to the with the Blasius solution's skin friction by loading the file and then plotting it with your solution. ([Download file here|^cf_blasius_Re1e4.xy]) \\ !step6_006.png|width=302,height=173! Also, you can change the symbol into lines by going to {color:#990099}{*}{_}Curves..._{*}{color} and click on the corresponding pattern that you like. Increase the {color:#990099}{*}{_}Weight{_}{*}{color} to 3 for readability. Both results should be fairly similar. !step6_007.png|width=298,height=255! [Higher Resolution Image|^step6_007.png] \\ h4. {color:#cc0000}Plot Velocity Profiles{color} *Results > Plots > XY Plot* Uncheck {color:#990099}{*}{_}Position on X Axis{_}{*}{color} and check {color:#990099}{*}{_}Position on Y Axis{_}{*}{color} under Options. Under {color:#990099}{*}{_}Plot Direction{_}{*}{color}, set X to 0 and Y to 1. Under {color:#990099}{*}{_}X Axis Function{_}{*}{color}, select {color:#990099}{*}{_}Velocity..._{*}{color}Then, change {color:#990099}{*}{_}Velocity Magnitude{_}{*}{color} to {color:#990099}{*}{_}X Velocity{_}{*}{color}. Finally under {color:#990099}{*}{_}surface{_}{*}{color}, select {color:#990099}{*}{_}outlet{_}{*}{color}. Before we are ready to plot, click on the {color:#990099}{*}{_}Axes..._{*}{color} button and rescale the y-axis from 0 to 0.12. Also, check the {color:#990099}{*}{_}Major Rules{_}{*}{color} and {color:#990099}{*}{_}Minor Rules{_}{*}{color} for both axes. Remember that you must click the {color:#990099}{*}{_}Apply{_}{*}{color} button when performing changes in each axis. Click {color:#990099}{*}{_}Plot{_}{*}{color}. !step6_008.png|width=298,height=255! [Higher Image Resolution|^step6_008.png] \\ To compare with the Blasius solution, download the solution here. Click {color:#990099}{*}{_}Load File..._{*}{color}and select the file you just downloaded. Then plot the solutions again to display both lines on the same graph. !step6_009.png|width=298,height=255! [Higher Resolution Image|^step6_009.png] \\ What is the noticeably different between two solutions? Why is the velocity overshoot 1 for FLUENT's solution? Now we will compare the velocity profile at two sections. Create another section in the middle of the plate. h4. Again, in the XY Plot window under *New Surface > Line/Rake* Check the {color:#990099}{*}{_}line tool{_}{*}{color} checkbox under Options and set the initial coordinate to _(0.5,0)_ and final coordinate to _(0.5,0.5)_. Under the {color:#990099}{*}{_}New Surface Name{_}{*}{color} field, type in *x_0.5* and then click the {color:#990099}{*}{_}Create{_}{*}{color} button to create the line. We can now plot and compare the velocity profile at the mid point and the outlet of the flow. Under {color:#990099}{*}{_}Surfaces{_}{*}{color}, select {color:#990099}{*}{_}outlet{_}{*}{color} and {color:#990099}{*}{_}x_0.5{_}{*}{color} and {color:#990099}{*}{_}Plot{_}{*}{color}. !step6_010.png|width=298,height=255! [Higher Resolution Image|^step6_010.png] \\ Go to [Step 7: Refine Mesh|FLUENT - Flat Plate Boundary Layer Step 7] |